A hybrid automatic repeat request (HARQ) manner may be used in a communications system for error control. In an HARQ technology, a polar code (polar codes) may be used as a mother code.
In an HARQ process, affected by a channel status and a status of an allocated radio resource, an actual code rate for a first transmission (an initial transmission) may be different, but used polar codes are the same. Therefore, when a difference between the actual code rate for the first transmission and a target code rate corresponding to the polar code is excessively large, there is a performance loss in the first transmission.